1. Field of the Invention
The present invention relates to an in-contact magnetic head slider configured to perform recording data to and reading data from a magnetic recording medium, a magnetic head assembly having the magnetic head slider, and a magnetic recording apparatus having the magnetic head assembly.
2. Description of the Related Art
In magnetic recording apparatuses (hard disc drives), increase in recording density is constantly required, and various techniques have been developed for this purpose. One example of such techniques is an in-contact magnetic head slider. For the in-contact magnetic head slider, recording and reading are performed while an end of the slider in the disc traveling direction is kept in contact with the magnetic disc by applying an air layer pressure to the air-bearing surface (slider surface) of the slider. According to this slider contact scheme, the magnetic spacing between the magnetic head and the magnetic disc can be decreased, which contributes to increase in recording density.
A basic concept of an in-contact magnetic head slider having an air-bearing surface that realizes forward flying and backward contact is known (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 7-307069). In this Publication, the center of gravity of a head suspension system is adapted to substantially coincide with the point of action of fluid force such that, when a vibrating force accompanying vibration of the disc or impact to the apparatus acts on the slider, most of the vibrating force can be supported by air layer rigidity so as not to change the contact force.
Another arrangement of an in-contact magnetic head slider is also known. In this slider, pad surfaces (squeeze pads) exhibiting a squeeze effect are arranged on the side of the air outlet edge, which ensure the reliability during loading and unloading (see Jpn. Pat. Appln. KOKAI Publication No. 2002-92836).
In Jpn. Pat. Appln. KOKAI Publication Nos. 7-307069 and 2002-92836, however, the point of action of the suspension load is set on the side of the air inlet edge of the slider, unlike in a flying slider, which poses issues in manufacturing costs and development efficiency. In order to develop an in-contact slider to which the same suspension as in the flying slider can be applied, the slider must be able to realize a low contact force even when the point of action of the suspension load is located at the center in the longitudinal direction thereof, in the same manner as in the flying slider. To achieve the above design, the following configuration may be conceivable. That is, a positive pressure-generating region supporting a high suspension load is arranged at the central portion in the longitudinal direction of the slider and a negative pressure-generating region is arranged immediately after a pad formed closer to the inlet edge than the positive pressure-generating region such that the substantial point of action of the load would be shifted toward the air inlet edge of the slider. If the negative pressure on side of the inlet edge is increased with this scheme, however, problems occur that a difference in contact force, depending on a radial position, is increased although the contact force itself is decreased and the contact force is increased under a condition of a reduced pressure.